The Sync Framework 2.0 that was just released today already has capabilities to allow you to synchronize to the SQL Azure enironment. Unfortunately we have not completed documentation on this for you, so this can be a bit of a daunting task right now.
However, at the PDC conference in Nov we are going to be talking a lot more about some of the new capabilities that we have implemented to make this easier to accomplish both for data (SQL Azure) and files (Windows Azure Blob).
LiamSr. Program Manager, SQL Azure and Sync Framework - http://msdn.microsoft.com/sync/